Sub-bottom profiling systems are employed to identify and characterize layers of sediment or rock under the seafloor. These systems also can be helpful in locating hard objects buried beneath the seafloor including shipwrecks. Magnetometers are mostly used during pipeline surveys, shipwreck surveys, and when buried ferrous materials at sea bottom need to be located. Additional information about objects (such as burial depth) can be collected by performing statistical analysis on shapes generated from magnetic field anomalies detected by several passes of a single magnetometer or with a multi-magnetometer array. We have employed sub-bottom profiling technology and magnetometer surveys to assist in many hydrographic surveys.